Well thats a new on for me..
Thought I'd heard most of the lame accuses in clinic avoiding prescribing a pump!
If you are on large amounts of insulin, a pump actually might enable you to reduce the amount! As when injecting insulin the larger the amount can effect the adsortion rate, so by the time all the insulin has been adsorbed by the body a certain percentage of this would be asorbed after the insulin has stopped having an effect on the blood sugar levels.. As the pump delivers much smaller amounts as it delivers basal/background insulin continualy over a 24 hour period, more insulin is adsorbed, so less required for back ground, to a certain extent similar with the bolous side of it, most pumps have a selection of bolus that can be delivered, a standard all in one hit (same as a jab) one that delivers the dose at a constant rate of a chosen period and another that delivers a portion of the bolus at once, then give a constant delivery of the rest over a chosen period..
I've not come across nor am I'm aware of the manufacturers suggesting that there is any limit to how much can be delivered, the only contrants is that of the cartridge which is 3ml so plenty of insulin to be had... The more you use on a daily bases the quicker you need to refill the cartridge of the pump...
I have come across one person, who used massive amounts of insulin a day due to having the double whammy of both T1 and T2 and being increditable resistent to insulin, they used a pump at first to avoid changed cartridges daily/twice a day, they kept up with manualy injecting background insulin, using the basal profile on the pump to fine tune the background/basal needs... They then went to swapping the standard strength u100 insulin u500 insulin, which is rare strength to obtain and needs importing from America to the UK on a per patient bases under a special important licence...
I would contact some of the pump suppliers, get some information of them concerning, max amounts etc... then go back to clinic and challange them concerning there decission...